U.S. Pat. No. 5,894,392 (McDonald), which is incorporated by reference herein in its entirety, allegedly recites a “power distribution unit for supplying temporary branch power has a 240-250 VAC input with input power line conductors L1 and L2, a neutral conductor N, and a ground conductor G. A supervisory circuit checks that the 240-250 VAC input is properly connected to the power distribution unit by requiring that the input voltage exceeds a supervisory circuit threshold voltage substantially greater than 120-125 volts. When that occurs, a contactor is enabled by the supervisory circuit to close first and second contacts therein to pass the 240-250 VAC on lines L1 and L2 therethrough to a 240-250 VAC ground fault interrupter protected circuit breaker outlet. A plurality of 120-125 VAC GFI module outlets are connected across either one of lines L1 and L2 at the output of the supervisory circuit and the neutral conductor N which bypasses the contactor. The supervisory circuit includes a diode bridge circuit connected across power line conductors L1 and L2 to convert a 240-250 VAC input to 240-250 VDC. A voltage threshold zener diode is connected in series with first and second relays across the 240-250 VDC, such that the zener diode ensures that the voltage required to operate the first and second relays is substantially greater than 120-125 VDC. The first relay operates contacts to activate the contactor, and the second relay operates contacts to bypass the neutral conductor N around the contactor.” See Abstract.
United States Patent Publication No. 20050122650 (Beasley), which is incorporated by reference herein in its entirety, allegedly recites a “portable electric power supply with a main contactor relay connected in electrical series with a manual safety switch and voltage sensing relay contactor between the neutral conductor and a power conductor of the power supply. A voltage sensing relay detects the voltages in the power supply and turns on the voltage sensing relay contactor when the voltages reach a minimum value. The safety switch is wired in parallel with a latching contactor. The main contactor relay activates a main power contactor and the latching contactor when the voltage sensing relay contactor and one or both of the safety switch and latching contactor are activated, and deactivates the main power contactor and latching contactor when the voltage sensing relay contactor is deactivated. When activated, the main power contactor connects power outlets to the neutral conductor and power conductors.” See Abstract.